单宁酸磷酸酯的合成及其抗氧化性能评价

以单宁酸为原料、三聚磷酸钠为磷酰化试剂、尿素为催化剂进行磷酸化反应合成单宁酸磷酸酯。通过正交实验优化最佳合成工艺,并利用磷含量计算产率,通过傅里叶红外光谱(FT-IR)、紫外光谱(UV)表征其结构。研究了单宁酸磷酸酯的电导性,并利用其对羟基自由基(·OH)和超氧阴离子自由基(·O_2~-)的清除能力评价了抗氧化性能。结果表明,最佳合成工艺条件为n(单宁酸)∶n(三聚磷酸钠)=1∶1、反应时间为18 h、反应温度为65℃,在此条件下的产率可达86.02%。产物的电导率与其质量浓度呈显著正相关,并在一定浓度下电导率比相应单宁酸高出10~15倍;当质量浓度为1 g/L时,产物与单宁酸对·OH和·O_2~-清除率分别为75%和55%。结果证明,在优化的最佳条件下产率较高,所合成的单宁酸磷酸酯具有较好的抗氧化活性。

Synthesis and Antioxidant Activity in Vitro of Tannic Acid Phosphate

Tannic acid was synthesized from tannic acid as raw material,sodium tripolyphosphate as phosphorylating reagent and urea as catalyst to phosphorylate tannic acid.The optimum synthesis process was obtainedby orthogonal test and the yield was calculated by using phosphorus content.The structure of the product was confirmed by FT-IR and UV.The electrical conductivity of tannic acid phosphate was investigated and the antioxidant properties were evaluated by the scavenging ability of hydroxyl radical (· OH)and superoxide anion radical(· O2-).The results showed that the optimal synthesis conditions were n(tannic acid):n(sodium tripolyphosphate)=1:1,reaction time 18 h,reaction temperature 65 ℃.Under the optimal conditions,the yield of the product was 86.02％.The conductivity of the product was positively correlated with the concentration and was 10～ 15 times higher than that of tannic acid at a certain concentration.When the mass concentration of 1 g/L,the clearance rates of · OH and· O2-were 75％ and 55％.The results showed that the yield of tannic acid phosphate was better under the optimized conditions,and the synthesized tannic acid phosphate had better antioxidant activity.